The headline number on an agency project quote is the smallest number you’ll pay over five years. The math nobody runs is what that $35K project actually costs once you add the maintenance retainer, the bug-fix retainer, the SEO that wasn’t included, and the year-three rebuild. Here is that math, in detail.
The composite cost worksheet
Let’s work a concrete example. You’re a 12-person professional services firm. You need a new website, basic SEO, Google Ads management, and analytics. Three project agencies quote you. You pick the mid-tier at $35,000 for the website build, six weeks of timeline, three rounds of revisions. The other services are negotiated separately. Here is what year one through year five actually looks like:
Year one
- Website project: $35,000 (the headline number)
- SEO retainer:$1,500/mo × 8 months — you started SEO mid-year because the project agency didn’t bundle it. That’s $12,000.
- Google Ads management:$1,000/mo × 12 months = $12,000. (Separate vendor; you couldn’t find an agency willing to do PPC under a project model.)
- Analytics setup:$2,500 one-time for proper GA4 + GTM — the project agency installed a default GA4 snippet, which doesn’t track conversions properly. A specialist firm fixes it.
- Hosting + maintenance:$200/mo × 12 = $2,400. Standard.
Year one total: $63,900. Notice that the $35K project headline is barely half the actual first-year cost. This is normal. Project-based pricing is structured to keep the headline low; the supporting work happens out-of-scope.
Year two
- Performance tuning:Six months in, the website loads in 4.2 seconds on mobile (Google’s threshold for "good" is under 2.5). The original agency offers a "performance optimization sprint" for $4,000. You take it.
- Plugin updates + security patches: Two of your installed plugins were abandoned by their maintainers. Migration to alternatives: $3,000.
- SEO retainer continues:$1,500/mo × 12 = $18,000.
- Google Ads management:$1,000/mo × 12 = $12,000.
- Hosting: $2,400.
- Conversion tracking re-fix:The PPC agency notices conversion events aren’t firing properly after a plugin update. Diagnostic + fix: $1,500.
Year two total: $40,900. Cumulative: $104,800. The website is paying for itself in leads, but the maintenance cost is steady.
Year three
- The design feels dated.Competitors have refreshed. Internal stakeholders want a refresh too. The original agency proposes a v2 at $42,000. (You don’t take the full rebuild; you take a $15,000 partial refresh of the homepage and main service pages.)
- The lead designer moved on. The new designer at the agency wants more revision rounds than the original spec allowed. Out-of-scope change orders: $4,500.
- SEO + PPC + hosting: $32,400 combined (same as year two).
- Analytics audit: Year-three accumulated noise in GA4 needs a cleanup. $2,000.
Year three total: $53,900. Cumulative: $158,700.
Years four and five
Years four and five settle into a steady-state of approximately $40,000/year combined for SEO, PPC, hosting, ad-hoc maintenance. By the end of year five your cumulative spend across all vendors is approximately $238,700.
The $35K project headline was 15% of your actual five-year cost.
What subscription pricing looks like for the same scope
For comparable work — website that gets iterated on, SEO that compounds, PPC managed in-house, analytics maintained — a subscription agency in the $800-$1,200/mo range delivers all of the above for $9,600-$14,400/year. Across five years: roughly $48K-$72K.
Against the $238,700 cumulative project-model spend above, that’s a five-year savings of roughly $167K-$190K— about 70-80% less. The professional services firm in our example is on the dramatic end; across the small businesses we’ve worked with, the typical five-year subscription savings vs project-model equivalent lands in the 50-70% range. Even the conservative end of that range is meaningful.
The math reliably favors subscription for businesses on a five-year horizon. It almost always favors subscription on a ten-year horizon.
Why the project model produces this delta
Three structural reasons:
- The headline is the bait.Project pricing is sold on the upfront number. The maintenance, retainer, and iteration work is sold separately, often after you’ve already committed to the project. Total-cost-of-ownership is opaque by design.
- Multi-vendor stacking compounds friction.When one agency builds the site, another runs SEO, a third runs PPC, and you maintain analytics yourself, every seam between vendors is a place where work falls through. The conversion-tracking re-fixes, the analytics audits, the "who’s responsible for this plugin update" questions — those are seam-cost.
- Project agencies don’t plan for compounding.SEO compounds over 18-36 months. Project pricing cuts the work off before the curve bends. You pay for the launch but not for the months when the launch starts to pay off — because that work is sold as a separate retainer.
How to run this math for your own situation
Take any project agency quote you’re considering. Add:
- The headline project number
- 12 months of expected ongoing retainer for the same scope, multiplied by 5
- One rebuild (50-100% of the original project cost) in year 3 or 4
- An estimated $5K/year in "seam costs" (re-fixes, ad-hoc work, vendor switch cost)
That’s your honest five-year number. Compare it to a subscription quote at the same monthly price × 60 + setup. Then decide.
We built a calculator that does the first part of this math automatically. It only models the headline numbers — the seam costs and rebuild costs are extras you’ll have to estimate separately — but it gets you 70% of the way there in 30 seconds.
The honest closing
We sell subscription. We’re biased. The bias comes from running this exact math for hundreds of small businesses, watching the project-pricing trap close on most of them, and deciding to build the alternative.
If your situation falls into one of the three scenarios where project pricing still wins, take that path. Otherwise, the math is what the math is.